Means for casting dental fillings.



APPLIUATIOH FILED OCT. 7, 1907.

Patented Jan. 18,1910.

UNITED STATES; ra'rnntr OFFICE. 4

JOHN P. ,LEDERLE AND FRANCIS A. LEDERLEQOE CHICAGO, ILLINOIS means ronoasrme DENTAL Funn es.

' To all whom. it may concern:

Cll

. clea r, and exact description.

Our invention relates to certain, new and useful improvements in moldsused by dentists for casting the fillings of teeth.

Heretofore in the prosecution of the art of casting dental fillings themeans employed were designed with a view to the casting of but onefilling at a time, and were so constructed that this casting had-t0 bemade in the center of the mold and did not allow for irregularities inthe shape of the castingswhich would make it more convenient to placethe sprue nearer one side of the flask than the other.

An object of our invention is to enable two or more castings to be madein a mold of V the size which heretofore was devoted to the making ofone casting.

Another object is to enable a casting to be made nearer one side of theflask than the other, and to locate the sprue at whatsoever point theirregular shape of the casting to he made would make it most convenient.A further object of our invention is to provide an improved sprue formerwhich can be conveniently inserted into the pattern of the cavity of thetooth of the patient when it is desired to remove the same, and isweighted so as'to hold the said pattern up out of contact from thesurface 11 on which the sprue former rests when it is aid down, and willform a countersink or'crucible for the metal around the mouth of thesprue regardless of whether it is located in the center of the mold ornot, substantially as hereinafter fully described and as particularlypointed out in the claims.

In the drawingsz-Figure 1 is a transverse vertical section of a flaskshowing our improved sprue former in connection with the same. Fig. 2 isa similar view with the sprue former removed. Fig. 3 is a plan view ofthe same. Fig. 4 isa plan view of the invention.

In the drawings, A represents a flask Specification of Letters latent.

Patented Jan. 18, 1910.

' Application filed 0mm 7; 1907. Serial No. 396,295.

. which :is; preferably. cylindrical in shape and 15 representsasprue-former consisting of a wire or rod, sa-y an inch in length havingits upper end bent into acircle or other snitably shaped loop I), andhaving mediate said loop and its lower end. a metal boss 0, preferably,of a diameter slightly less than mehalf that of the innercirciunferelicc of the flask. The weight of the looped end of thesprue-former is so much greater than its opposite end that when saidsprue-former is laid down. the boss serves as a fulcrum and the straightend of the former which is adapted to be stuck into the plastic patternwill always be raised from the surface u on which said former rests.This boss is 0 an inverted,coneshape'with the conical sides thereoffarthest from the loop, although it may be made almost hemispherical,substautially as shown by the boss (I of the sprue D shown in Fig. 5 ofthe drawings. TheIloop b affords the operator a suitable finger graspwith which to grasp the sprue when it is desired to insert the same intothepattern or 1 plastic material formedi-n the cavity of the tooth ofthe patient when it is desired to withdraw the same; and provides themeans for suspending the plastic pattern on its lower end within theflask at any suitable .5

point. The plaster of paris or other suitable molding material, while ina very soft condition, is poured into the flask until the latter isfilled to about the level of its upper edge. The pattern is theninserted into the soft moldin material by means of the sprueformer untithe boss thereof is embedded up to its upper side, thus completelyenveloping the pattern. When the molding material'is-se't thesprue-former is pulled upward with sufiicient force to extract the lowerend of the same from the pattern, and withdraw it from the flask. \Vhenthus withdrawn the sprue-former leaves a sprue a: and a countersink orcrucible e in the upper surface of the mold. The mold is then heated tosolidify the-molding material and melt the material of the pattern untilit, the latter, volatilizes, or until it is so lique- 2 j i j 946,677-

by any suitable means, in any position desired within themold so thatthe sprueholder can be made to lead from the highest part of anirregular pattern, no matter where said highest point may be located,and thus avoid any overhang in the molding chamber and avoid forming anair space in the same above the end of the sprue-h'ole.

\Ye do not desire to be confined to the exact' length of the sprueformeras shown, nor to the shape of the boss of the same, for it is obviousthat they may be changed, and the loop omitted without departing fromthe spirit of our invention.

\Vhat we claim as new is 1'; A device of the character describedcomprising a crucibleformer having tapered sides, and a fixed rodextending therethrough that is so constructed that the portion therei ofopposite the tapered sides overbalanees the latter. 1

2. A device of the character described comprising a crucible formerhaving tapered sides, and a gate pattern consisting of a rod the upperend of which projects above the top of said crucible former and isprovided with a finger-grasp that overbalancesthe opposite end of saiddevice.

EEQA device of the character described comprising a crucible formerhaving tapered sides, and a gate pattern consisting of a rod extendingthrough and projecting beyond said former the end thereof above the topof said former shaped into a loop that overbalances the oppositeendofsaid rod.-

v In testimony whereot we have hereunto set our hands and seals this 4thday of October, A. D. 1907. Q

JOHN P. LEDERLE. IjL. 8.] FRANCIS A. LEDERLE.

lVitnesses FRANK D. THOMASON, E. K. Lonny.

